Reaction of Sc strips, ScCl3, and graphite at 860-1000°C gives Sc7Cl10C2 in quantitative yields, with transport occurring at the higher temperatures; adventitious carbon will also produce the phase. The compound has been shown to be isostructural with Er7I10 by single-crystal X-ray diffraction (a=18.620 (4) Å, b=3.4975 (6) Å, c=11.810 (2) Å, β=99.81 (2)o; space group C2/m, Z=2, R=0.029, Rw=0.046 for 676 reflections, MoKα, 27Cl10, from which the heavy atom arrangement can be derived by displacement of all metal atoms by b/2 so as to convert chlorine functions on the metal chain from face-capping to edge-bridging. The driving force for this is thought to be the reduction of carbon-chlorine repulsive interactions. Core and valence XPS data for Sc7Cl10, Sc7Cl10Cl2, Sc2Cl2C, ScCl3, and Sc are presented to demonstrate the appearance of a carbide-like state for the interstitial, the presence of two different types of scandium in the first two comopounds, the oxidation of the chain that accompanies the carbon insertion, and a substantial Sc-C covalency. The latter arises through mixing of the interstitial's 2s and 2p valence orbitals with metal-metal bonding cluster orbitals of the same symmetry.
ASJC Scopus subject areas
- Inorganic Chemistry
- Physical and Theoretical Chemistry
- Ceramics and Composites
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Condensed Matter Physics